This P20 proposal entitled, ?Experiential and Child Factors that Determine Acquisition of Orthographic- Phonological Regularities in a Quasi-Regular Writing System: An Integrated Behavioral/Computational/Neurobiological Approach? responds to the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) invitation for LD Innovation Hubs, FOA (RFA-HD- 17-003). This LD Hub specifically addresses the P20 FOA (RFA-HD-17-003) by addressing issues of etiology, manifestation, prevention, and remediation of RD and by explicitly responding to the FOA target area 3, ?historically challenging, yet established, research topics involving populations at risk for or diagnosed with one or more LDs [in our case RD] where progress has been limited despite high public health need.? The overarching goal of this LD Hub project is to lay the foundation for a generation of research that situates educational practices (e.g., diagnosis, curriculum, instruction, & intervention) in a novel computational theory of individual development informed by state of the art computational modeling and neurobiological measures of development and learning, and conversely, that aligns these theories more closely with the challenges confronting educators of both typically developing (TD) children and more specifically children with reading disability (RD). The primary motivation for our Hub is the realization that the next frontier of scientific work in the field of RD must increase the understanding and integration of the neurobiological and cognitive underpinnings of word reading performance across the early elementary grade span with emphasis on factors that explain individual differences, elucidate the complex relationship between experience and an array of cognitive skills that represent RD, and inform effective instruction and remediation. The long-term goal of this LD Hub is to develop the next generation of scientifically informed word-reading interventions required to ameliorate the significant word reading deficits of RD children with the most intractable learning difficulties (i.e., nonresponders to effective instruction). Within this scientific framework computational modeling approaches serve a critical connective role in bridging educational and neurobiological advances. Our Hub therefore adopts an integrated approach to better understand the neurocognitive bases of individual differences in word reading development in an opaque and quasi-regular writing system, English. Specifically, our Hub brings together a diverse and talented group of researchers, mentees, and institutions to examine the experiential (exogenous) and child-specific (endogenous) factors that determine acquisition of orthographic-phonological (O-P) knowledge at different subword granularities using behavioral, computational modeling, and neurobiological methods. Findings will enrich understanding of the processes that influence individual differences in word reading development in TD and RD children and significantly inform the development of effective curriculums for children who struggle to learn to read.